The subject matter herein relates generally to a system for electrically connecting electrical cables to a printed circuit board.
Various communication or computing systems use electrical connectors to transmit data signals between different components of the systems. An electrical connector may mechanically and electrically connect to a printed circuit board, for example. Typically, the printed circuit board includes conductive pads on a planar surface. Conductive wires extending from cables are soldered to the conductive pads in order to connect the printed circuit board to another component, such as another printed circuit board, connector, or the like.
However, each printed circuit board has a limited amount of space in which to position wires, traces, and the like. Often, differential pair signaling is used with respect to electrical systems. A cable may include signal wires and a ground or drain wire. The cable may connect to the printed circuit board.
Typically, a differential pair includes a positive signal wire and a negative signal wire. Each of the positive and negative signal wires are soldered to pads on the printed circuit board. The ground wire is typically soldered to the board in order to shield the differential pair from another differential pair. Because space is limited on the printed circuit board, the ground wire is often soldered to the printed circuit board and routed to the cable on the surface of the printed circuit board in a circuitous manner. In doing so, however, the signal wires may not be symmetrical about the drain wire. An asymmetric relationship between the signal wires and the drain wire typically leads to a signaling imbalance between the signal wires. That is, a positive differential signal may not be the exact opposite of a negative differential signal, or vice versa. Therefore, larger printed circuit boards may be used so that the drain wires can be directly soldered to pads on the board with the signal wires being symmetrical with respect to the drain wire. Unfortunately, however, use of larger printed circuit boards within a confined space of an application, such as within a computer system, may not be possible.
Additionally, directly soldering the wires to pads on the printed circuit board takes up additional space. Attempts to directly solder the wires to the printed circuit board may prove difficult or even impossible. Further, the increased amount of solder between closely bunched signal traces on the printed circuit board may degrade signal integrity. That is, when neighboring differential signal pairs are too close to one another, the neighboring differential signal pairs are susceptible to cross-talk and interference, which degrades signal integrity.
In general, as data rates continue to increase, there is a need to control electrical noise through cable assemblies in order to achieve desired performance. Often, the cables are terminated to printed circuit boards in order to create a connection between the cables and the printed circuit boards. In very small, miniaturized connectors, the area used to terminate the cables to the printed circuit boards is typically extremely small. As such, the cables may be in close proximity to one another. However, as the cables get closer to each other, noise and cross-talk between the cables increases. If the noise and cross-talk exceed a particular threshold, the cables are unable to operate as intended.